ARM: OMAP: Make dummy wrapper if the OMAP_GPIO_SWITCH is not set

OMAP_GPIO_SIWTCH is optional, so omap_reister_gpio_switches will be null.
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/asm-arm/arch-omap/gpio-switch.h

@@ -48,7 +48,11 @@ struct omap_gpio_switch {
 };
 
 /* Call at init time only */
+#ifdef CONFIG_OMAP_GPIO_SWITCH
 extern void omap_register_gpio_switches(const struct omap_gpio_switch *tbl,
 					int count);
+#else
+#define omap_register_gpio_switches(tbl, count)	do { } while (0)
+#endif
 
 #endif